In recent years, 3D images have attracted attention. As schemes of viewing the 3D images, schemes (hereinafter referred to as glasses type schemes) of putting on glasses that open a left-eye shutter at the time of display of one image between 2-viewpoint images and open a right-eye shutter at the time of display of the other image and viewing the alternately displayed 2-viewpoint images are general.
However, in such glasses type schemes, viewers are required to purchase glasses separately from 3D image display devices, thereby reducing viewer's purchase willingness to purchase. Since the viewers are required to put on glasses at the time of viewing, the viewer may feel troublesome. Accordingly, demands for of viewing schemes (hereinafter referred to as non-glasses type schemes) of viewing 3D images without putting on glasses have increased.
In such non-glasses type schemes, viewpoint images of 3 or more viewpoints are displayed so that viewable angles are different for each viewpoint, and thus viewers can view 3D images without putting on glasses when merely viewing any 2-viewpoint images with the left and right eyes, respectively.
As methods of displaying 3D images in the non-glasses type schemes, methods of acquiring a predetermined viewpoint color image and a depth image, generating a multi-view color image including a viewpoint other than the predetermined viewpoint based on the color image and the depth image, and displaying the multi-view color image have been devised. Here, the multi-view refers to 3 or more viewpoints.
As methods of encoding a multi-view color image and a depth image, methods of encoding the color image and the depth image separately have been suggested (for example, see Patent Literature 1).